This invention relates to a window construction capable of permitting or perventing light transmission. More particularly, this invention relates to a window construction which utilizes polarizer panels and a moveable wave retarder-polarizer panel to permit or prevent light transmission through the window.
It has been proposed in U.S. Pat. Nos. 3,528,722 and 3,663,089 to provide window structures including a fixed polarizer member and a rotatable polarizer member which permits regulation of light transmission through the window structure depending upon the position of the absorption axis of the rotatable polarizer relative to the position of the absorption axis of the fixed polarizer. These structures are useful in limited applications where windows of generally a circular shape are employed such as in airplane windows. However, such structures are undesirable in most windows which are rectangular or relatively large since a space larger than the windows would be necessary in order to permit rotation of the rotatable member. In addition, in larger windows, such as in the sunroof of an automobile or in building windows, the power requirements and housing requirements for a rotatable window mechanism would be undesirably expensive.
It is desirable to provide a window structure capable of preventing or permitting transmission of light which does not require space in addition to that occupied by the window viewing area. Furthermore, it is desirable to provide such a window structure which does not require the rotation of a window component to regulate light transmission.